Catheter drive

ABSTRACT

A catheter for use in a blood vessel, comprising an elongate body having an axis, a lumen along said axis, a proximal opening at one end, connected to the lumen and a front tip at a distal end of the body; and an elongate hydraulic fluid column in said lumen and adapted to apply a pushing force to said front tip in a distal direction, said force being applied at an application point. Optionally, the body comprises two tubes, one or which extends in response to the pushing force.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. Ser. No. 10/303,064filed on Nov. 25, 2002, the disclosure of which is incorporated hereinby reference.

FIELD OF THE INVENTION

The present invention relates to devices and methods for catheternavigation.

BACKGROUND OF THE INVENTION

Blood vessels can suffer from various diseases, in particulararteriosclerosis, in which obstructions form in a lumen of a bloodvessel, narrowing or clogging it. Emboli can also cause clogging ofblood vessels. A common treatment method for narrowing is inserting acatheter with a balloon at its end to a clogged portion of the bloodvessel, inflating the balloon and possibly leaving a stent at theclogged location, to keep the blood vessel open.

In some implementations, a guide wire is brought to the narrowedlocation, and then the catheter is pushed over the guide wire. If thecatheter is soft, helping it negotiating curves, it may be difficult toconvey the pushing force along the catheter from outside the body to thetip. If the catheter is stiffer, it may be less able to negotiate sharpcurves. In either case, excessive pushing forces may damage the bloodvessels.

One solution suggested in the art is providing a catheter with varyinglevels of stiffness along its length—stiff at its base and soft at itsend.

In colonoscopy, U.S. Pat. No. 6,485,409, the disclosure of which isincorporated herein by reference, suggests a colonoscope which isadvanced by air or liquid pressure. This solution is apparently notsuitable for catheters used in blood vessels, especially in narrowdiameter blood vessels, such as cardiac arteries and brain arteries, forexample due to size considerations and geometry of surfaces tat wouldcontact blood.

SUMMARY OF THE INVENTION

A broad aspect of some embodiments of the invention relates to acatheter advancing mechanism in which force is applied, via a hydraulicmechanism, near a distal tip of a catheter. In an exemplary embodimentof the invention, the applied force causes the distal tip of thecatheter to pull along with it at least a part of the catheter proximal(e.g., further from the tip) of where the force is applied. In anotherexemplary embodiment of the invention, the applied force pushes a partof the catheter, starting at a point well inside the body, relative to asecond part of the catheter which extends to outside of the body anddoes not move.

In an exemplary embodiment of the invention, the catheter comprises atleast two tubes inside the body, an inner tube and an outer tubeenclosing at least part of the inner tube. In an exemplary embodiment ofthe invention, the tips pulls an inner tube section of the catheter outof an outer tube section of the catheter. In an alternative embodiment,the tip pulls the outer tube section of the catheter along an inner tubesection of the catheter.

In an embodiment where the outer tube is pulled, a significant length ofmoving catheter body may be in contact with the enclosing blood vessel(or optional delivery sheath). In an embodiment where the inner tube ispulled, a shorter moving length is generally in contact with the sheathand/or the enclosing blood vessel.

In an exemplary embodiment of the invention, the force is applied usingfluid pressure which is optionally applied from outside the body.Optionally, a sliding fluid seal is provided between the outer and innertubes. The fluid may be provided, for example, in the inner tube, orbetween the inner tube and the outer tube. Optionally, the same fluidsource and path is used for advancing and for balloon inflation.Optionally, a valve is provided to release pressure and prevent overpressuring of the fluid.

Optionally, additionally to fluid pressure, a solid mechanical elementforce may be used for advancing. For example, a stylet may be insertedthrough the inner tube to advance the tip. Optionally, such a stylet isused to apply vibration and/or tapping to the tip.

Optionally, a guide wire is provided for the catheter to ride on. Insome embodiments the guide wire passes through the fluid path. Inothers, it does not.

In an exemplary embodiment of the invention, the catheter portion whichextends is too soft to be reliably pushed from outside the body along aguide wire to blocked coronaries. However, it is stiff enough to supportpushing from a small distance and/or pulling, inside the body.Optionally, the extension mechanism allows a relatively smaller diametercatheter to be used.

In an exemplary embodiment of the invention, the force is applied veryclose to the tip, for example at a distal part of a balloon portion ofthe catheter, or less than 5 cm, for example, between 0 and 15 mm, lessthan 70 mm, less than 30 mm or less than 10 mm, from a proximal part ofthe balloon portion. In other embodiments, a greater offset is providedbetween the catheter tip and the location of application of the force,for example, less than 40 cm or less than 30 cm. In an exemplaryembodiment of the invention, the offset of the force application pointis minimized to allow a relatively rigid catheter portion to reach neara working area (e.g., the aorta) and from there push forward arelatively soft portion (e.g., to a blocked coronary.

Optionally, the catheter includes a stop that prevents over-extension ofthe catheter tip. Alternatively or additionally, the catheter includes alock, outside the body, which (optionally selectively) prevents relativemotion of the two tubes, or places a limit on such motion, for example,a limit on amount of motion and/or a limit on speed of motion.

In an exemplary embodiment of the invention, a stop wire is providedattached to the moving tube and extending out of a catheter base, andincluding a brake section selectively movable on the wire. In oneexample, the distance between the brake section and the catheter basedetermines an allowed extension. Optionally, the brake is anacceleration brake which resists sudden motion more than slow motion.

An aspect of some embodiments of the invention relates to a ballooncatheter having a seal attached thereto, such that the seal can sealfluid flow between the balloon catheter and a guiding catheter,optionally without making any change in the guiding catheter fromstandard guiding catheters. Optionally, fluid is provided between theballoon catheter and the guiding catheter, to advance the ballooncatheter. Optionally, the seal is adaptive and can seal the ballooncatheter to a range of guiding catheter inner diameters.

An aspect of some embodiments of the invention relates to a mechanicallyactuated valve for a catheter. In an exemplary embodiment of theinvention, fluid pressure is provided along a lumen of the catheter, anda valve selects whether the fluid will be allowed to apply pressure to afirst location and/or to a second location. In one example, the fluidexpands a balloon at a first location and applies force to advance acatheter tip, at a second location.

Various valve configurations may be provided. In an exemplary embodimentof the invention, a wire is pulled to remove a blocking element from alumen of a balloon. When not pulled, the blocking element serves as abase against which advancing force is applied. Alternatively oradditionally, a wire is rotated to turn a blocking element so that anaperture therein matches a lumen to which pressure is to be applied.

An aspect of some embodiments of the invention relates to a catheter inwhich a tip of the catheter advances and lengths the catheter thereby.This lengthening is supported by a section of tube that is in acollapsed configuration outside the body, for example, folded axially,wound in a spiral or folded accordion style. In an exemplary embodimentof the invention, the section of tube is adapted to come in contact withblood. Alternatively or additionally, the section of tube serves as alumen for expanding a balloon.

There is thus provided in accordance with an exemplary embodiment of theinvention, a catheter for use in a blood vessel, comprising:

-   -   an elongate body having an axis, a lumen along said axis, a        proximal opening at one end, connected to the lumen and a front        tip at a distal end of the body; and    -   an elongate hydraulic fluid column in said lumen and adapted to        apply a pushing force to said front tip in a distal direction,        said force being applied at an application point. Optionally,        said application point is nearer said front tip than said        proximal opening. Alternatively or additionally, said proximal        opening is adapted to be outside a human body, when the catheter        is in use.

In an exemplary embodiment of the invention, said catheter is configuredso that said liquid material does not drain into said blood vessel. Inan exemplary embodiment of the invention, said column is adapted to beadvanced from outside a body.

In an exemplary embodiment of the invention, said body comprises acollapsed tube which extends from said tip to outside of said body andwhich said pushing force extends collapsed tube.

In an exemplary embodiment of the invention, said tip pulls along aportion of said catheter, having a length of at least 5 times a diameterof the catheter, said length being pulled by said tip when pushing forceis applied to said tip.

In an exemplary embodiment of the invention, said body comprises afirst, inner, tube and a second, outer tube, said tubes at leastpartially axially overlapping, wherein said pushing force extends onetube relative to the other tube. Optionally, said tip pulls at least aportion of said one tube with it when pushing force is applied to saidtip. Optionally, said pulled section is too soft to be reliably pushed adistance of more than 500 mm in a human body, when the catheter is inuse.

In an exemplary embodiment of the invention, said tip pulls along a tubeother than said tubes when pushing force is applied to said tip.

In an exemplary embodiment of the invention, at least a portion of saidone tube is adapted to be stored outside a human body when the catheteris in use and extends out of a catheter base of said catheter.

In an exemplary embodiment of the invention, at least a portion of saidone tube is adapted to be stored outside a human body, when the catheteris in use, in a configuration having a shortened axial dimension.

In an exemplary embodiment of the invention, said inner tube extendswhen said force is applied.

In an exemplary embodiment of the invention, said outer tube extendswhen said force is applied.

In an exemplary embodiment of the invention, only one of said inner andsaid outer tubes substantially extends when said force is applied.

In an exemplary embodiment of the invention, said fluid column iscarried between said two tubes.

In an exemplary embodiment of the invention, said fluid column iscarried within the inner tube.

In an exemplary embodiment of the invention, the catheter comprises atool attached at said tip. Optionally, said tool comprises a balloonattached at said tip.

In an exemplary embodiment of the invention, the catheter comprises aseparate tube with a lumen for inflating said balloon. Alternatively oradditionally, said balloon is attached to a metallic inflation tube.Alternatively, said inner tube serves as a lumen for inflating saidballoon. Optionally, said inner tube serves as a lumen for inflatingsaid balloon and not for said fluid column.

In an exemplary embodiment of the invention, said balloon is inflatedvia a lumen which carries said fluid column. Optionally, said balloon isinflated using a higher pressure than used for extending said catheter.Alternatively or additionally, the catheter comprises a valve at saidballoon for selectively allowing liquid flow into said balloon.Optionally, said valve is a pressure sensitive valve. Alternatively,said valve is an externally actuated valve. Optionally, said valve is astop valve in which a block is retracted from a port to said balloon toallow fluid under pressure to enter the balloon. Alternatively, saidvalve is a rotating stop valve having at least two configurations, andin which a block is rotated from one configuration to a second one ofsaid configurations to selectively seal or not seal a port to saidballoon.

In an exemplary embodiment of the invention, said balloon inflation tubeis adapted to be stored outside a human body, when the catheter is inuse. Optionally, said tube is stored in an axially collapsed state.

In an exemplary embodiment of the invention, said tube is adapted toextend at least 50 mm.

In an exemplary embodiment of the invention, said one tube is adapted toextend at least 150 mm.

In an exemplary embodiment of the invention, said one tube is adapted toextend at least 250 mm.

In an exemplary embodiment of the invention, said one tube is adapted toextend no more than 500 mm.

In an exemplary embodiment of the invention, the catheter comprises atleast one stop which prevents relative motion between the two tubesgreater than a pre-set distance.

In an exemplary embodiment of the invention, at least one of said atleast one stop is outside of said body.

In an exemplary embodiment of the invention, at least one of said atleast one stop is not in contact with said fluid.

In an exemplary embodiment of the invention, said at least one stopcomprises a wire extending out of said catheter and at least one movablebrake section mounted on said wire.

In an exemplary embodiment of the invention, said stop, when engaged,prevents liquid flow therethrough.

In an exemplary embodiment of the invention, said stop, when engaged,does not prevent liquid flow therethrough.

In an exemplary embodiment of the invention, said stop, is locatedwithin 50 mm of a proximal end of the extending tube.

In an exemplary embodiment of the invention, said stop, is located at adistance of at least 50 mm from a proximal end of the extending tube.

In an exemplary embodiment of the invention, when said tube is fullyextended, said stop is located at a distal end of the non-extendingtube.

In an exemplary embodiment of the invention, when said tube is fullyextended, said stop is located at a position spaced less than 50 mm froma distal end of the non-extending tube.

In an exemplary embodiment of the invention, the catheter comprises aplurality of axially spaced stops.

In an exemplary embodiment of the invention, said stop is an elementaxially shorter than 5 mm. Alternatively, said stop is an elementaxially longer than 5 mm.

In an exemplary embodiment of the invention, the catheter comprises atleast one seal between said tubes. Optionally, said at least one seal isadapted for a particular outer tube inner diameter. Alternatively, saidat least one seal is adapted for a range of outer tube inner diameters.

Optionally, said at least one seal comprises a plurality of axial spacedseals. Alternatively, said at least one seal comprises only a singleseal.

In an exemplary embodiment of the invention, said at least one seal actsas a stop for preventing over-extension of said one tube.

In an exemplary embodiment of the invention, the catheter comprises anextension limiter which prevents steps of extension greater than apre-set distance. Optionally, said pre-set extension step limitation isuser-settable.

In an exemplary embodiment of the invention, the catheter comprises alock configured to selectively lock said inner tube to said outer tubeand preventing motion.

In an exemplary embodiment of the invention, the catheter comprises alock configured to selectively couple said other tube to said body.

In an exemplary embodiment of the invention, the catheter comprises apressure valve configured to release pressure of said working fluidabove a certain liquid pressure.

In an exemplary embodiment of the invention, the catheter comprises acontroller configured to control extension of said one tube. Optionally,said controller is adapted to extend said tube by a controlled amount.Alternatively or additionally, said controller is adapted to extend saidtube by setting a pressure level to be achieved in said liquid.Alternatively or additionally, said controller is adapted to advancesaid catheter. Alternatively or additionally, said controller is adaptedto synchronize a locking of said catheter with inflation of a balloonportion of said catheter. Alternatively or additionally, said controlleris adapted to retract said tube relative to said catheter. Optionally,said controller is adapted to synchronize said retraction with advancingof said catheter.

In an exemplary embodiment of the invention, the catheter comprises aguiding sheath surrounding said tubes.

In an exemplary embodiment of the invention, the catheter comprises aguide wire, wherein said catheter is adapted to ride on said guide wire.Optionally, said catheter is configured so that said guide wire passesthrough said inner tube to outside a human body, when the catheter is inuse. Alternatively, said catheter is configured so that said guide wirepasses between said inner tube and said outside tube to outside a humanbody, when the catheter is in use. Alternatively, said catheter isconfigured so that said guide wire passes outside of said outside tubeto outside a human body, when the catheter is in use. Alternatively oradditionally, said catheter is configured so that said guide wire passesoutside of a guiding sheath to outside a human body, when the catheteris in use.

In an exemplary embodiment of the invention, the catheter comprises aballoon at said tip. Optionally, said guide wire passes through aninflation lumen of said balloon. Alternatively, said guide wire has aproximal exit from said balloon adjacent said balloon. Optionally, saidballoon has a thick base from which said guide wire exits.

In an exemplary embodiment of the invention, said exit is less than 20mm from said balloon.

In an exemplary embodiment of the invention, said guide wire passeswithin an inflation lumen of said balloon.

In an exemplary embodiment of the invention, said guide wire exits saidcatheter from said extending tube at a point distal from a most distalpoint of said non-extending tube.

In an exemplary embodiment of the invention, said guide wire exits saidcatheter from said extending tube at a point proximal to a most distalpoint of said non-extending tube.

In an exemplary embodiment of the invention, said guide wire passesthrough a seal between the two tubes.

In an exemplary embodiment of the invention, said guide wire passes athrough a liquid path of said column in said catheter.

In an exemplary embodiment of the invention, said guide wire passes onlyoutside of a liquid path of said column in said catheter.

In an exemplary embodiment of the invention, said inner tube comprises astandard balloon catheter, not manufactured for fluid control andwherein said liquid is carried between said outer tube and said standardballoon catheter.

In an exemplary embodiment of the invention, said inner tube comprises astandard balloon catheter having an adjustable seal mounted thereon, andwherein said liquid is carried between said outer tube and said standardballoon catheter. Optionally, is a guiding catheter.

In an exemplary embodiment of the invention, said outer tube has anouter diameter of less than 3 mm.

In an exemplary embodiment of the invention, said outer tube has anouter diameter of less than 2 mm.

In an exemplary embodiment of the invention, said outer tube has anouter diameter of less than 1 mm.

In an exemplary embodiment of the invention, said inner tube has anouter diameter of less than 1.5 mm.

In an exemplary embodiment of the invention, said inner tube has anouter diameter of less than 0.5 mm.

In an exemplary embodiment of the invention, said application point isless than 500 mm from a most distal point of said catheter.

In an exemplary embodiment of the invention, said application point isless than 350 mm from a most distal point of said catheter.

In an exemplary embodiment of the invention, said application point isless than 70 mm from a most distal point of said catheter.

In an exemplary embodiment of the invention, the catheter comprises anoffset element between said application point and said tip, whichapplication point conveys said force from said column towards said tip.

In an exemplary embodiment of the invention, the catheter comprises apush wire adapted to apply a second force to said tip. Optionally, saidpush wire applies said second force at a substantially same axialposition as said application point. Alternatively or additionally, thecatheter comprises a controller configured to allow a short advance ofsaid wire, suitable for passing a narrowing in a blood vessel.

In an exemplary embodiment of the invention, the catheter comprises abase hub adapted to remain outside a human body, when the catheter is inuse. Optionally, said base hub has only a single port for liquidpressure. Alternatively, said base hub has a plurality of ports forliquid pressure. Optionally, at least one of said ports has a coveradapted to remain closed when fluid inside said port is at 5 atmospheresof pressure or more.

In an exemplary embodiment of the invention, said base hub comprises apressure release valve. Alternatively or additionally, said base hubcomprises a port for a guide wire. Alternatively or additionally, saidbase hub comprises a port for a pushing wire. Alternatively oradditionally, said base hub comprises a port for a valve control wire.Alternatively or additionally, said base hub comprises a port for anextension restricting wire. Optionally, said port is configured to locksaid wire when said base is pressurized above a pre-set pressure value.

In an exemplary embodiment of the invention, said base hub comprises aselector configured for selecting which of a plurality of lumens of thecatheter fluid pressure will be coupled to.

In an exemplary embodiment of the invention, said base hub comprises aclosable opening suitable for selectable user access to a lumen of thecatheter through the door. Optionally, said opening is adapted to bequickly opened by hand.

In an exemplary embodiment of the invention, said base hub includes acatheter storage section having a length, wherein said length is lessthan 80% of a length of a catheter section stored therein.

There is also provided in accordance with an exemplary embodiment of theinvention, an extendible catheter comprising:

-   -   a base section adapted to remain outside a human body, when the        catheter is in use;    -   an elongate body having a lumen and a distal tip and including a        collapsed section stored in said base section; and    -   a liquid column adapted to apply force to said body adjacent        said tip. Optionally, said collapsed section is stored in a        folded configuration. Alternatively or additionally, said        collapsed section is stored in an axially pleated configuration.        Alternatively or additionally, said collapsed section is stored        in a coiled configuration. Alternatively or additionally, said        collapsed section is stored in an axially folded configuration        such that part of said section is inside-out.

In an exemplary embodiment of the invention, the catheter comprises anouter tube out of which said body exits in an uncollapsed state.Alternatively or additionally, the catheter comprises a second collapsedtube inside of said collapsed section. Optionally, said second collapsedtube is a balloon inflation tube.

In an exemplary embodiment of the invention, the catheter comprises afeeding nozzle for uncollapsing said collapsed section.

There is also provided in accordance with an exemplary embodiment of theinvention, a catheter with a mechanically activated fluid valve,comprising:

-   -   an elongate body having a lumen, said lumen defining a fluid        path;    -   a tool activated by said fluid and situated at a distal section        of said elongate body;    -   a fluid valve at said distal section adapted to selectively        convey fluid to said tool; and    -   a mechanical actuator coupled to said valve and extending        outside of said body to control said valve. Optionally, said        tool comprises a fluid-inflated balloon. Alternatively or        additionally, said catheter is adapted to have a distal section        thereof extended distally by said fluid.

In an exemplary embodiment of the invention, said actuator rotates saidvalve. Alternatively, said actuator retracts a blocking section of saidvalve. Optionally, said actuator retracts a blocking section of saidvalve such that in a maximally retracted position the blocking sectionallows for passage of fluid from said lumen to said tool.

There is also provided in accordance with an exemplary embodiment of theinvention, a method of deploying a catheter-carried tool, comprising:

-   -   inserting an extendible catheter into a blood vessel of a body;        and    -   extending a distal section of the catheter to reach a target        area, by at least a distance of 50 mm. Optionally, the method        comprises activating said tool at a distal end of said extended        section. Optionally, said extending comprises extending by        providing fluid pressure into said catheter.

In an exemplary embodiment of the invention, said tool comprises aballoon.

In an exemplary embodiment of the invention, inserting comprisesinserting along a guide wire.

In an exemplary embodiment of the invention, inserting comprisesinserting through a guiding catheter/sheath.

In an exemplary embodiment of the invention, the method comprisesadvancing said catheter after said extending.

There is also provided in accordance with an exemplary embodiment of theinvention, a method of testing a catheter, comprising:

-   -   attaching the catheter to a source of hydraulic pressure; and    -   increasing said pressure to extend a distal section of the        catheter by at least 50 mm.

BRIEF DESCRIPTION OF THE FIGURES

Exemplary, non-limiting embodiments of the invention will be describedbelow, with reference to the following figures, in which the sameelements are marked with the same or similar reference numbers indifferent figures:

FIG. 1 is a schematic illustration of an exemplary catheter system inuse, in accordance with an exemplary embodiment of the invention;

FIG. 2 is a cross-sectional view of a catheter advancing system inaccordance with an exemplary embodiment of the invention;

FIG. 3 is a flowchart of a method of using a catheter system inaccordance with an exemplary embodiment of the invention;

FIGS. 4A and 4B show a catheter system in which an inner tube extendsrelative to an outer tube, in accordance with an exemplary embodiment ofthe invention;

FIG. 4C shows a stop mechanism for a catheter, in accordance with anexemplary embodiment of the invention;

FIGS. 5A and 5B show a variant of the catheter system of FIGS. 4A and4B, in which a short seal is used, in accordance with an exemplaryembodiment of the invention;

FIG. 5C is a close-up of a section of the catheter of FIG. 5A, showing aseal in accordance with an exemplary embodiment of the invention;

FIG. 5D is a close-up of a hub section of the catheter of FIG. 5A, inaccordance with an exempla embodiment of the invention;

FIG. 6 shows a catheter system with a guide wire in contact with workingfluid, in accordance with an exemplary embodiment of the invention;

FIG. 7 shows a catheter system that is a variant of that of FIG. 6, witha forward section enlarged, in which an extended seal is used, inaccordance with an exemplary embodiment of the invention;

FIG. 8A shows a catheter system, in which a single lumen is used forboth extension and balloon inflation, in accordance with an exemplaryembodiment of the invention.

FIGS. 8B and 8C show variants of the catheter of FIG. 8A, showingballoon lumen provision methods, in accordance with exemplaryembodiments of the invention;

FIG. 9A shows a catheter system, in which an inner tube thereof iscollapsed outside the body, in accordance with an exemplary embodimentof the invention;

FIG. 9B shows a variant of a hub base of the catheter of FIG. 9A, inaccordance with an exemplary embodiment of the invention;

FIG. 9C is a top view of a pleated tube, in accordance with an exemplaryembodiment of the invention;

FIG. 10 shows a catheter system similar to that of FIG. 9A, except thata separate tube is provided for inflation of a balloon section of thecatheter, in accordance with an exemplary embodiment of the invention;

FIG. 11 shows a catheter system in which a single lumen is collapsed byaxial folding thereof, in accordance with an exemplary embodiment of theinvention;

FIG. 12 shows a back section of a catheter system, in which a separatetube is provided for a balloon section of the catheter, in accordancewith an exemplary embodiment of the invention;

FIG. 13 shows a catheter system with a single lumen, in which amechanically actuated valve is provided, to selectively allow inflationof a balloon section thereof, in accordance with an exemplary embodimentof the invention.

FIGS. 14A and 14B show a catheter system, similar to that of FIG. 13,with a different back limiter design, in accordance with an exemplaryembodiment of the invention;

FIGS. 15A and 15B show a catheter system, similar to that of FIG. 13,with a different valve design, in accordance with an exemplaryembodiment of the invention; and

FIG. 16 shows a catheter with an external balloon inflation tube, inaccordance with an exemplary embodiment of the invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Overview

FIG. 1 is a schematic illustration of an exemplary catheter system 100in use, in accordance with an exemplary embodiment of the invention. Aheart 102 includes a coronary vessel 104 with a narrowing 106 (e.g.,caused by arteriosclerosis plaque, an old stent, etc. or another typesof diseased tissue, such as an emboli). Catheter system 100 includes aguide wire 108 on which rides a catheter 110, at least partly in aguiding catheter/sheath 112. Catheter 110 has a distal tip 111, whichoptionally includes a balloon 114 and/or a stent 116. In an exemplaryembodiment of the invention, a distal section 118 of catheter 110 isadvancible from sheath 112, using a force applied at or about distalsection 118, as described below. A control system 120 is optional usedfor controlling this advance. A lock 122 is optionally provided to lockcatheter 110 to sheath 112 and/or lock movement of distal section 118 tosheath 112 and/or the rest of catheter 110.

It should be noted that while the figure shows navigation to a coronaryvessel, a similar system may be used for navigation to a blood vessel inthe brain or another organ. Also, a vascular (or non-vascular) problemother than a narrowing may be treated, for example, radiation deliveryto a tumor.

As will be described below, in some embodiments, guiding catheter 112and/or guide wire 108 are omitted. Alternatively or additionally, therelative placement (e.g., which encloses which) is changed in someembodiments from what is shown in FIG. 1.

Exemplary Catheter with Moving Outer Tube

FIG. 2 is a cross-sectional view of a catheter 200, in accordance withan exemplary embodiment of the invention. Catheter 200 has an outer tube202 and an inner tube 204, with a lumen 206. Outer tube 202 is sealed ata distal end 228 thereof, for example by an optional balloon 218,described in more detail below.

In use, a pressure source 208, for example a syringe, is used to injectfluid into lumen 206. If a liquid is used, this causes pressure increasein a lumen section 207 of outer tube 202 that is contiguous with lumen206. A sliding fluid seal 214 is provided between tubes 202 and 204.Thus, tube 202 acts as a piston for a cylinder body defined by tube 202.Increase in the internal pressure of lumen 207 causes relative motion oftube 204 (the piston) and tube 202 (the cylinder). In an exemplaryembodiment of the invention, tube 202 is freer to move and it moves byadvancing balloon 218 in a direction 212, which is also associated withflow of fluid in a direction 210 into lumen section 207. It should benoted that the pressure increase applies force to distal end 228 of tube202, near the distal end of catheter 200 itself. For example, a distance230 between a tip 232 of balloon 218 and end 228 can be as small as 30mm or less, such as 20 or 10 mm or less. Optionally, an inversionballoon is used, in which tip 232 is inverted inwards.

Optionally, seal 214 comprises a gasket, optionally formed out of tube204, for example as a series of rings. Alternatively, tubes 202 and 204are a snug fit, (at least for a length of an allowed relative advance)and no special seal is required. If an inter-tube volume 216 exists, itmay be provided with a lubricant. Optionally, this lubricant serves as aseal. In an exemplary embodiment of the invention, the lubricantcomprises a hydrophilic material as known in the art which swells whencontacting water, thereby sealing, and also becoming greasy whencontacting water. In an alternative embodiment of the invention, volume216 serves as a conduit for leaking fluid. Alternatively or additionallyseal 214 is a leaky seal, for example, to ensure fluid in volume 216 toserve as a lubricant and/or to serve as a pressure valve which preventsover pressuring of lumen section 207. Tube 202 is optionallysubstantially non-expandable, for example, expanding less than 1% at 20atmospheres. Optionally, one or both of tubes 202 and 204 are adapted tonot stretch axial under working conditions. In one example, one or morelongitudinal fibers (e.g., plastic or metal wires) are embedded in thetubes, to add tensile strength to the tubes. In one example, three orfour circumferentially evenly spaced wires are used.

In an alternative embodiment of the invention, no real seal 214 isprovided. Instead, the force on end 228 is a function of the rate offluid inflow and the rate of fluid outflow via volume 216. In general,outflow is inhibited by friction and boundary effects in volume 216.These types of effects in lumen 206 can be overcome by increasing thepressure, thus generating an inequality between inflow and outflow. Thisrate may be controlled, for example, by increasing or decreasing thepressure provided by source 208. Thus, it is possible to more finelycontrol the force that advances balloon 218, for example to preventinadvertent damage or to allow passing of sharp bends and/or narrowings.

In an exemplary embodiment of the invention, balloon 218 is provided atthe distal end of catheter 200. A separate inflation lumen 220 (e.g., atube) is optionally provided inside of tubes 202 and 204, and isoptionally inflated by a separate pressure source 222. Exemplaryvariations on methods of inflating balloon 218 and providing fluidthereto, are described below in other embodiments of the catheter. Inother embodiments of the invention, a different tool is provided insteadof or in addition to a balloon and tube 220 may be used, for example tocarry wires and/or materials other than for inflation. In an exemplaryembodiment of the invention, tube 220 is a metallic flexible tube, whichmay assist in reducing kinking and/or enhancing pushability.

Guide wire 108 optionally exits through an exit hole 224, for exampleafter passing through a dedicated tube (not shown) in balloon 218. Otheroptions, for example using well known balloon designs may be used. Somesuch options and new options are described below in other embodiments.

One or more radio-opaque markers are optionally provided, for example, amarker 226 near a distal end of catheter 200, at seal 214 and/or at end228. These markers may be used for positioning catheter 200 at variousoperational stages, for example as described below and/or for estimatinga degree of extension of the catheter.

While sheath 112 (FIG. 1) is not shown, it may be provided. Optionally,the sheath will reach until adjacent seal 214. Guide wire 108 optionallytravels in the sheath between the sheath wall and outer tube 202 ofcatheter 200.

Optionally, seal 214 is formed by belling out inner tube 204, forexample using heat. In this construction, when fluid pressure increases,it urges the belled section more strongly against outer tube 202,increasing sealing.

Exemplary Process

FIG. 3 is a flowchart 300 of an exemplary process of deploying catheter200, in accordance with an exemplary embodiment of the invention. Aswill be noted below, the catheters of the invention may be used withother processes as well.

At 302, a decision as to where to guide the catheter, is optionallymade. In some cases, for example if lumen 222 is used to inject contrastfluid during a diagnosis procedure, the exact target area may not beknown ahead of time. In other cases, a particular narrowing 106 is to betreated by balloon and/or stent.

At 304 a port is opened into a main artery or vein (e.g., a femoralartery), depending on the approach used to reach a target area in thebody.

At 306, guiding catheter/sheath 112 is optionally inserted through theport. In the example of a coronary artery, the sheath may be inserted asfar as the aorta or even into a main coronary artery.

At 308, guide wire 108 is optionally advanced through sheath 112 and tonarrowing 106. Various guide wire navigation techniques as known in theart may be used. In some embodiments of the invention, two guide wiresare used. First a thick guide wire and then a thin guide wire, forexample as known in the art of catheter navigation.

At 310, catheter 200 is advanced along guide wire 108 (if any) andthrough sheath 112 (if any) to within a certain distance from narrowing106. This distance may depend on several factors. For example, astandardized method may be to advance to about the distal end of sheath112. Alternatively or additionally, catheter 200 may be advanced bypushing until as far as it can be advanced. Alternatively oradditionally, catheter 200 may be advanced to within an extensiondistance ability thereof from narrowing 106.

At 312, source 208 is activated to increase the internal pressure inlumen 207, causing an advancing of outer tube 202 and balloon 218. In anexemplary embodiment of the invention, as the advancing force is appliedat near the distal tip of catheter 200, it is more probably that most ofthe force is directed to advancing the catheter along guide wire 108rather than to digging a part of catheter 200 into a wall. Optionally,if needed, a pressure burst is applied to lumen 207, to help passthrough narrowing 106. As will be noted below, over advancing of theballoon is optionally prevented by restraining tube 202 relative to tube204.

At 314, guide wire 108 is optionally retracted. In some embodiments,guide wire 108 is removed earlier. In others, guide wire 108 stays inplace until the end of the procedure.

At 316, balloon 218 is optionally inflated (e.g., using pressure source222), optionally deploying stent 116 (if it is provided). Othertreatments may be applied instead or in addition to balloon expansionand stent placement In an exemplary embodiment of the invention, lock122 is applied prior to inflation to prevent motion of balloon 218during inflation. Optionally, the position of balloon 218 is verifiedusing imaging techniques (e.g., fluoroscopy, CT imaging and/or MRIimaging), prior to inflation.

At 318, balloon 218 is optionally deflated, so that it can be retractedrelative to stent 116.

At 320, catheter 200, sheath 112 and/or guide wire 108 are retracted.The retraction may include reversing the pressure at source 208 to causeretraction of tube 202 relative to tube 204. In an alternativeembodiment, catheter 200 is simply pulled back.

At 322, catheter 200 is optionally repositioned, for example, byre-advancing tube 202 relative to tube 204.

Variations on Process

There are many techniques of advancing catheters known in the art.Catheter 200 may be used with many of these techniques, optionally withsuitable modifications so that the ability of some embodiments of theinvention to extend a catheter forward, are utilized.

In one example of an alternative catheter advancing technique, a guidewire and a catheter in accordance with the present invention areadvanced as a pair. The guide wire is advanced a short distance and thenthe catheter is pushed forward and/or extended forward the shortdistance.

In another example of an alternative catheter advancing technique,catheter 200 is advanced without a guide wire, and is optionallyprovided with a soft tip.

In another example of an alternative catheter advancing technique,sheath 112 is not provided and catheter 200 is advanced along the guidewire. A potential disadvantage of this technique is that a considerablelength of tube 202 is pulled along the blood vessels wall every timecatheter 200 is extended forward. The extension mechanism may be used,for example, starting from the entry into the femoral artery or at someintermediate point. Alternatively, catheter 200 is pushed as far as itcan be easily pushed before extending catheter 200. If a sheath isprovided, for example, extension of the catheter may start at a pointother than the entry into the coronary system, for example, before theaortic arch or after one or two branches of coronary arteries.

In another example of an alternative catheter advancing technique,catheter 200 is used to crawl forward, in relatively small steps. Inthis technique, end 228 is extended and then tube 204 is advanced.Optionally, end 228 is retracted during the advance of tube 204 so thatend 228 stays in a same position relative to a blood vessel. Optionally,this technique uses tube 202 is a slightly more rigid guide wire fortube 204.

In another example of an alternative catheter advancing technique,catheter 200 is extended as far as it can be extended and then retractedso that balloon 218 is in the correct position. Alternatively, once thecorrect position is reached, catheter 200 is pulled back and extended atthe same time and/or in small increments so that balloon 218 remains inits correct position. This method is useful for catheter designs(described below) in which a same lumen is used for extending catheter200 and for expanding balloon 218, and by completing the extension thereis no danger of the balloon expansion moving balloon 218. In otherembodiments, a position lock is used to prevent such motion.

Controller Logic

Referring back to FIG. 1, controller 120 which is used to control themotion and/or extension of catheter 200 may be of various types and/orabilities. Optionally, controller 120 is manually controlled.Alternatively it is remotely controlled, for example as a robot. In someembodiments, some of the controlling logic is distributed to other partsof the catheter, for example to the moving tubes.

In an exemplary embodiment of the invention, catheter 200 is advancedusing a fixed volume technique, in which controller 120 provides acertain increase in the volume of the working fluid, which translatesinto a certain increase in the volume of lumen 207 and therefore acertain extension of tube 202.

In an alternative embodiment of the invention, a force based techniqueis used, for example if seal 214 is leaky. In this technique, controller120 is used to apply a force, for example gradually or as an impulse, tocause an extension of tube 202. Once a desired extension is achieved (orshortly before, to accommodate response time) the force is stopped.Optionally, a combined force/position extension technique is used, inwhich a maximum advance (or a step size) is set by coupling a stop toeach of tubes 202 and 204. Force is then applied to extend or retracttube 202, with the total extension (or retraction) being limited to thedistance between the stops. An exemplary such controller is shown inFIG. 4C, below.

It should be noted that, in some embodiments of the invention, the forceneeded to achieve an advance increases as a function of the number andsharpness of the bends across which the catheter was already extended.

Optionally, a stop is provided, for example as described below, forexample a lip on one or both of the tubes, which prevents extension oftube 202 beyond a certain amount (e.g., when the lips meet).

Optionally, controller 120 is used also for retracting of tube 202towards tube 204, for example by reducing a working fluid volume or byapplying a negative pressure.

Various power sources may be used. For example, a push syringe or asyringe with a piston that is screwed into its body may be used. In analternative manual embodiment, a knob which rolls along a tube is usedto increase pressure in the tube by forcing working fluid to advancealong the tube. In an alternative embodiment, an electrically controlledpump or fluid or pressure source is used. Optionally, the force isapplied non-hydraulically (e.g., using a rigid object, such as a stylet)from the outside the body, which force is conducted to a fluid filledchamber inside the body, to provide the hydraulic extension describedherein.

Optionally, controller 120 indicates a degree of extension, for exampleshowing a marking made on tube 202 in a window thereof. Alternatively,the degree of extension may be measured using an optical encoder.Optionally, the amount of extension for a given amount of pressure orforce is learned and may be used, for example, while retracting, toretract an amount equal to the last advance. Alternatively oradditionally, the extension is tracked for the purpose of providing aclosed loop control, in which a user requests a step of extension andpressure is stopped once such an extension is determined. In anexemplary embodiment of the invention, the controller comprises amicro-controller chip with a memory. Optionally, such a memory is usedto learn and/or store values for static and dynamic friction of thecatheter extension mechanism, for example determined during acalibration process in manufacture or during use.

Controller 120 optionally includes other types of extension sensors, forexample an optical encoded which reads markings on the extending tube.In an alternative embodiment, one or more radio-opaque markers areprovided on the extending and/or non-extending tubes, so that theirrelative position is visible using x-ray imaging.

Controller 120 optionally includes other types of sensors, for example,a leakage sensor and a working fluid pressure sensor. Optionally, anaccurate pressure gauge, for example a digital gauge is used. Leaks mayshow as a gradual pressure loss.

In an exemplary embodiment of the invention, controller 120 and/orcatheter 200 include limiting means. In one example, a maximum advanceper step is limited. Alternatively or additionally, controller 120 canlock two or more of guide wire 108, sheath 112, inner tube 204 and outertube 202. Which pairs can be locked depend, for example on theparticular embodiment. In another example, a maximum pressure limiter isprovided, for example a valve may be provided outside the body, to leakover-pressure. The maximum pressure is optionally settable.Alternatively, a drain valve may be defined from lumen 206 to volume216.

Optionally, controller 120 can also advance or retract the whole ofcatheter 200, for example by moving inner tube 204. Optionally,controller 120 can synchronize the movement of tube 202 and tube 204, sothat the crawling method described above is achieved, e.g., tube 202 isretracted even as tube 204 is advanced. It should be noted that thistype of synchronization can also be achieved with a mechanicalcontroller in which rotation of a knob simultaneously advances tube 202and reduces volume and/or pressure in lumen 206.

While many of the examples describes a liquid working fluid, such assaline solution or other suitable materials may be used, for examplebio-compatible materials or lubricating materials. Optionally, ananti-coagulant is provided in the fluid. In embodiments where the fluidis expected to leak to the treated area, various treatmentpharmaceuticals may be provided in the working fluid. Optionally, aradio-opaque component is provided in the fluid. In some embodiments ofthe invention, a gaseous working fluid, such as CO₂, is used. It shouldbe noted that volume 216 can provide a safe path for any such gas toleave the body without coming in contact with any tissue.

Materials and Structure

Catheters in accordance with exemplary embodiments of the invention maybe made of various materials, including those known in the art ofcatheter construction, for example, polyethylene, nylon, PBX, Teflon andother plastics, rubbers and latex. Various coatings are optionallyprovided, for example, silicone or hydrophilic or hydrophobic coatings.Optionally, a same coating is used on an extending tube both to reducefriction with an enclosing, non-extending tube and to reduce friction orother negative interaction with blood flow and/or blood vessel walls.

In particular embodiments of the invention, the catheter, or at leastthe extending part thereof is made of a softer material than would beuseful for pushing a catheter from outside a body. For example, thecatheter or the extending part may be as soft as a softest section(e.g., a most distal section proximal of the balloon) of a standardcatheter such as J&J Cordis E95, J&J Cordis “Aqua” (e.g., T3) or BostonScientific “Maverick”. Some elasticity is often useful. In one example,the catheter may be too soft to be effectively and reliably pushed morethan 30 cm or 50 cm in the body, in straight sections or in convolutedsections, such as in the coronary system or brain system. In brainapplications, the extended part may be longer, softer and of a smallerdiameter than in coronary applications.

Exemplary outer diameters of the extending section of the catheter are 2mm, 1.5, 1 mm, 07 mm, 0.5 mm or smaller, intermediate or largerdiameters. The non-extending sections can have an outer diameter of, forexample, less than 3 mm or less than 2 mm or a smaller, intermediate orgreater diameter.

In some embodiments of the invention a metallic tube is used as aninflation lumen for the balloon, also optionally providing some kinkresistance, pushability and/or ability to apply tapping and/or vibrationto obstructions (e.g., using a vibrating means as known in the art).

A non-moving tube (e.g., an outer tube), if it stays in the aorta (orother main vessels) may be stiffer than an extendible tube (e.g., aninner tube). Optionally, such a stiffer tube may be stiff enough to actas a guiding catheter and allow a separate guiding catheter to beomitted.

In such an embodiment, the guiding catheter and balloon carrying sectionare optionally advanced together over the guide wire, until the pointwhere only the balloon carrying section is advanced.

In an exemplary embodiment of the invention, the catheter can be madewith smaller dimensions, for example having an outer diameter of between0.4 and 3 mm, or smaller.

While the term “tube” is used, various, non-circular cross-sections maybe used as well. In addition, while concentric tubes are generallydescribed, this is not a required feature and the tubes may benon-concentric.

In an exemplary embodiment of the invention, considerable forces can beapplied at the tip of the catheter. For example, a 5 French catheter mayapply as much as 160 grams or more at its distal tip. Optionally,smaller forces, such as up to 140 or 100 grams are applied.Alternatively, greater forces, such as 200 grams or more are applied.These forces may reduce for smaller diameter catheters, for examplebeing a linear or quadric function of the catheter dimensions.Optionally, the force applied is a significant fraction (e.g., 20%, 30%,50% or more) of a product of the catheter cross-section and the appliedpressure. As can be appreciated, this may depend, for example on thehydraulic cross-section of the catheter as well as on the pressure losesalong the catheter. Optionally, the achieved forces have a high raiserate.

Catheters with Moving Inner Tube

FIGS. 4A and 4B show a catheter 400 in which an inner tube 404 extendsrelative to an outer tube 402. A balloon 418 is provided at a distal endof inner tube 404. A lumen 406 of inner tube 404 serves for inflation ofballoon 418, while a volume 416 between the two tubes serves to providea fluid column for advancing tube 404 and balloon 418. One possibleadvantage of providing a working fluid in volume 416 is to reducefriction between tubes 402 and 404.

While a seal between the two tubes can be axially short (e.g., asdescribed below), in an exemplary embodiment of the invention, arelatively long sealing tube 414 is used. Tube 414 can be, for example,10 mm, 20 mm, 40 mm, 80 mm, 200 mm or longer. One potential advantage ofusing a long tube is that the contact with the inner and/or outer tubecan be less tight while still inhibiting or preventing leakage (e.g.,based on boundary effects).

Optionally, sealing tube 414 has more than one function. One optionalfunction, sealing, may be provided by a part of the tube (e.g., even avery short section thereof, as in other seals described herein). Anotheroptional function is prevention/reduction of kinking. Optionally,sealing tube 414 is made slightly rigid. Another optional function,force extension, is described next. In other embodiments, for example asdescribed below, the working fluid is inside inner tube 404, so it isless likely to leak out. Optionally, the working fluid includes acontrast material, so that leakage can be identified using imaging, forexample fluoroscopy.

Optionally, the distal end of tube 414 contacts one or more protrusions450 formed on inner tube 404. As the fluid column abuts the proximalpart of seal 414, seal 414 conveys the applied force to protrusions 450and thereby advances tube 404. This optionally allows the force to beapplied at a more distal location. Optionally, at least part of seal 414can extend past outer tube 402. FIG. 4A shows catheter 400 in anextended configuration and FIG. 4B in a non-extended configuration.Optionally, seal 414 is mounted to one of tubes 402 and 404.

In an exemplary embodiment of the invention, catheter 400 has a maximumextension length, for example 300 mm for coronary uses, 500 mm for brainuses or 50 mm for advancing past obstructions. Optionally, this maximumextension length is enforced by at least one pair of stops, a stop 448on outer tube 402 and a stop 449 on inner tube 404. It should be notedthat these stops, even if not at a proximal end of tube 404, aregenerally near the most distal end of tube 404, when extended. Ifmultiple stops are provided, fluid pressure may apply a pushing force atmultiple points along tube 404. In the embodiment shown, the stops whenthey contact each other do not prevent further flow of liquid. Onepotential advantage of this design is allowing retraction by applicationof vacuum. Another potential advantage is that this allows maximum forceto be applied even near an end of the extension. In an alternativeembodiment the stops also seal. Optionally the lack of blocking allowsthe stops to be larger without a danger of inadvertently blocking volume416. Alternatively or additionally, the stops serve as spacers betweenthe tubes. Multiple spacers, even without a stopping function may beprovided for spacing the tubes. Optionally, this reduces friction, tothose points of contact. Optionally, the most proximal stop of tube 404is made by belling an end (or middle section) of tube 404, for exampleby heat and/or distortion, to have a greater diameter.

In an exemplary embodiment of the invention, multiple axially spacedstops are provided so that the relative extension of the tubes can stopat multiple locations. A small amount of overshoot may be amended, forexample by pulling back the catheter or the extended tube. Optionally,the intermediate stops are not absolute, for example a sufficient,optionally known, force will over come them. Alternatively oradditionally, relative rotation of the tubes will allow one stop toslide by the other stop. Alternatively or additionally, the stops arelocated in a base section 440 of the catheter, where a suitablemechanism can be used to expand the outer tube or compress the innertube so the stops slide by each other. In an alternative embodiment ofthe invention, stop 448 is provided as part of base 440, and may be, forexample, adjusted axially. An exemplary stop design is shown in FIG. 4C,below.

A potential advantage of multiple stops is allowing a user to vary theextension by known amounts, for example extending or retracting to acertain stop or a certain number of stops. For example, after extendingto just before a stop, catheter 400 itself may be advanced the distancebetween stops tube 404 retracted to just after a stop, thereby leavingballoon 418 at a same body location. In another example, a stop can beused to prevent an overshoot effect when applying a high pressure topass a narrowing or other obstruction, by the extension stopping at thenext stop.

A fluid port 442 is optionally provided for injecting fluid underpressure (e.g., using controller 120 or a syringe, as described above).The same port is optionally to inflate balloon 418 by selectivelyconnecting port 442 to inner tube 404. In an alternative embodiment ofthe invention, once balloon 418 is positioned base 440 is opened and asecond or same pressure source is attached to a proximal side of tube404. Optionally, tubes 402 and 404 are locked prior to such opening.Alternatively or additionally, stops 448 and 449 may be designed tointerlock and prevent retraction of tube 404 once advanced. Base section840 maybe of various lengths. For example, if tube 404 is not folded, itmay be, for example, 20, 30 or 40 cm long. If a folded tube is used(e.g., as described below), a shorter section may be provided, forexample less than 20 cm.

Optionally, sheath 112 is provided, as described above. Optionally, asheath lock 446 is provided to lock outer tube 402 to a sheath base 444,to prevent relative motion between sheath 112 and catheter 400. In someembodiments, if such a lock is not provided, rather than tube 404extending, tube 404 may jump or move away from the body. The locking tosheath base 444 optionally prevents this.

Various mechanism as known in the art may be used for sealing betweenouter tube 402 and sheath 112, for example, a tight fit, a rubber gasketand a valve.

In the embodiment shown, balloon 418 is provided with a thick base 452,through which guide wire 108 passes and exits through a guide wire port224 defined in the base. This allows for rapid/exchange type guide wireusage. The distance between port 224 and the proximal end of balloon 418can vary between embodiments, for example being less than 100 or 50 mm,possibly as little as 10 mm or down to about 0 mm. The distance may alsobe greater than 0 mm, for example, greater than 5 or 10 mm. In otherembodiments of the invention, guide wire 108 passes through theinflation lumen of balloon 218.

In the embodiment shown, guide wire 108 lies outside of sheath 112. Inother embodiments described below this can change, for example, theguide wire may be inside or outside the sheath, inside or outside thecatheter, in contact with the working fluid and/or inflation fluid ornot, passing through sheath base 444 and/or catheter base 440, or not.

When extending catheter 400 past a blockage there may be a danger ofovershoot, in which a high pressure applied to overcome the blockagewill, once the blockage is passed, translate into a large rapidextension. In an exemplary embodiment of the invention, friction isapplied to tube 404, inside base 440, to reduce such overshoot.Optionally, such friction is controllable. Alternatively oradditionally, a temporary stop may be place to limit a maximumextension.

A volume-based extension mechanism is optionally used, in which eachquantity of fluid injected into port 442 is translated into apre-determined extension, so overshoot is not a problem. This isoptionally provided if catheter 400 has reduced leakage. Optionally, anelastic membrane or chamber is provided in base 440, to allow theinjected fluid to translate into a pressure buildup even withoutextension. Optionally, a pressure relief valve is provided in base 404to prevent over pressuring (which may cause leakage). Optionally, therelease pressure of this valve is user settable. Alternatively oradditionally, a valve is formed in inner tube 402, such that fluid canleak from tube 44 into tube 404 if the pressure is too great.Optionally, the elasticity of catheter 400 itself is used to allow forpressure buildup.

Wire Stop

FIG. 4C shows a wire stop mechanism, in accordance with an exemplaryembodiment of the invention. A wire 460 is attached to a back section ofinner tube 404 and extends out of hub base 440, through a port 4666, forexample. When tube 404 extends, it pulls wire 460 along with it. Anoptional brake section 464 is provided on wire 460 to control suchextensions. In one example, a screw 472 attached to a spring 470 and apad 468 cooperate to allow a friction between pad 468 and wire 460 to beset. At a maximal setting, the distance between brake 464 and port 466set a maximum extension possible. Optionally, one or more small brakes(not shown), for example bumps in the cable are used to preferentiallystop wire 466 when such bumps reach port 466. In another example, brake464 is an acceleration break which prevents too fast a motion of wire460 through it. Many acceleration brakes are known in the art, forexample utilizing a non-straight bore in brake 464, for wire 460.

In an exemplary embodiment of the invention, valve 466 has the designshown, in which increased intra-hub pressure will cause the port to moresnugly engage wire 460 and possibly reduce leakage.

Such a wire stop may be used in other embodiments of the invention.However, it may be useful to attach the wire to a more distal part oftube 404, possibly to a base of balloon 418 (or its equivalent) in someembodiments.

Short Seal Variant

FIGS. 5A and 5B show a catheter 500 which is the same as catheter 400,except that sealing tube 414 is replaced by a short seal 514 mounted onan inner tube 504 or an outer tube 502 of catheter 500. The referencenumbers in FIG. 5 are the same as in FIG. 4, except for being increasedby 100. In this and other figures, same parts with same functions have athe same last two digits, such elements will not generally bere-described.

It should be noted that using a short seal moots the use of tube 414 foradvancing force in a distal direction.

FIG. 5C shows the details of an exemplary seal design for seal 514. Inthis design, seal 514 comprises a base section 568 attached to innertube 504 and an elongate, more flexible portion 564. Optionally, portion564 is flexible enough to change its effective diameter, possiblyfitting with various outer tube diameters 402. Optionally, this type ofseal is used to seal a balloon catheter to a guiding catheter, using theguiding catheter as the outer tube.

In an exemplary embodiment of the invention, seal 514 is mounted betweena forward protrusion or adhesive point 560 and a rear protrusion and/oradhesive point 562. There may also be a layer of adhesive (or heatsealing maybe used) to assist attachment

In an exemplary embodiment of the invention, seal 514 contacts outertube 502 at a limited tip area 566 of seal 514. Possibly, this reducesfriction.

In the embodiment shown, seal 514 has a design which increases thecontact force between tip 566 and tube 502, as the fluid pressure insidevolume 516 increases. Optionally, a same type of seal, in an oppositedirection, is used to prevent ingress of blood into the catheter system.

Other seal designs may be used as well, for example, ridges on one orboth tubes, o-rings, short sections of tube and/or magnetic fluids.

Exemplary Hub Design

FIG. 5D shows an exemplary hub design, in accordance with an exemplaryembodiment of the invention. Hub 540 comprises a body 582 and a back584. In an exemplary embodiment of the invention, body 582 is attachedusing an adhesive layer 580 to outer tube 502. Back 584 is optionallytransparent so that the extension of tube 504 therein can be viewed Back584 is optionally attached to body 582 using a quick connection, forexample a snap connection 586, or a half-turn and lock connection. AnO-ring 588 optionally helps seal the connection.

After tube 502 is advanced, back 584 is removed and tube 504 is inflatedto inflate balloon 518. In an exemplary embodiment of the invention, acap 592 is provided on a proximal section 590 of tube 504. Optionally,this cap is a screw cap. Alternatively, it is a snap cap. It is notedthat during operation of some embodiments of the invention, the pressurein hub base 540 should generally be greater than that of tube 504,ensuring that cap 592 does not fall off. In this design, fluid form port542 can surround inner tube 504 from all sides. It should also be notedthat there is generally sufficient space around cap 592 to allow fluidflow, so that all of base 540 is at a same pressure.

Variant with Second Seal and Guide Wire in Liquid

FIG. 6 shows a catheter 600 with several features, any one of which canbe used on its own. A first feature shown in FIG. 6 is that outer tube602 includes a stop 648 at a distal end thereof and which engages a seal614. Seal 614 also acts as an inner tube stop (e.g., like 449 in FIG.4). Optionally, this allows the use of a standard balloon catheter toact as an inner tube 604, only requiring attachment of seal 614 thereto.Optionally, stop 648 serves as a second seal to reduce leakage or as abackup.

A potential disadvantage of this design is that seal 614 and the pointof application of force to the distal part of catheter 600 are displacedfrom a balloon tip 618 by the amount of maximum extension.

Another feature shown in FIG. 6 is that a guide wire port 624 of balloon618 is proximal of seal 614. Thus, guide wire 108 travels in a volume616 between the two tubes and optionally exits through an exit port 650in a base 640 of the catheter. Optionally, a special tube is providedfor carrying the guide wire to prevent its contact with the workingfluid. Alternatively or additionally, a narrow lumen (not shown) isprovided for guide wire 108 in tube 604, the lumen being narrow enoughthat very little or no fluid leaks through.

In an alternative embodiment of the invention, port 624 is distal ofseal 614 and an aperture (not shown) is provided for passage of guidewire 108 through seal 614. Alternatively, a port near balloon 618 may beprovided, as described above. A removable cap 651 for inflation of tube604, is shown. Optionally, tube 604 is partially filled with fluid, evenprior to balloon inflation, so that tube 604 does not collapse.Alternatively, such collapsing is useful in that it prevents blockage ofthe volume between the tubes by kinking and bending of the catheters asthey are inserted.

Variant with Force Applied Near Catheter Tip

FIG. 7 shows a catheter system similar to that of FIG. 6, in which astop 748 of an outer tube 702 does not touch an inner tube 704. Instead,a seal 714 includes an extension 715 which has a lumen contiguous with avolume 716 between tube 704 and tube 702. Extension 715 is adapted toslide past stop 748. In this way, the liquid column reachessubstantially to balloon 718 (or less, if desired). Optionally, asshown, stop 748 is adapted to engage and stop a proximal portion of seal714.

A potential advantage of this design is that while the seal between tube702 and tube 704 is formed of two contacting surfaces (stop 748 and seal714), this contact is optionally not provided during most of theextension process, possibly reducing friction. Some amount of sealing isoptionally provided by seal 714 even without contacting stop 748.Alternatively, stop 748 is in contact with and optionally seals toextension 715. Optionally, as shown, the distal section of seal 714includes a ratchet mechanism to prevent retraction of tube 704, oncecompletely extended. Alternatively, the design shown is used to offsetseal 714 from an end of tube 702. Alternatively or additionally, anoffsetting protrusion (e.g., proximal of stop 748, for example by 5 mm)is provided on the inside of tube 702.

In an alternative embodiment of the invention, guide wire 108 passesthrough a port in seal 714 itself.

Single Fluid Lumen Catheter

FIG. 8A shows a catheter system 800, in which a single lumen is used forboth extension and balloon inflation, in accordance with an exemplaryembodiment of the invention. Catheter 800 comprises an outer tube 802and an inner tube 804 with a lumen 806. Unlike catheter 400, the workingfluid for extending catheter 800 is in lumen 806. When liquid isinjected through a fluid port 842 in a base section 840 of catheter 800,inner tube 804 and its attached balloon 818 extend. In the embodimentshown, lumen 806 continues unobstructed to the distal tip of balloon818, where it applies its advancing force. A volume 816 between thetubes is optionally provided with a lubricant. Alternatively oradditionally, one or both of the tubes is coated with a low frictioncoating, for example, a silicone coating or a hydrophilic coating, forexample “Rotaglide” by Boston Scientific, USA. Alternatively oradditionally, some of the working liquid leaks through an inner tubestop 849 into volume 816. An outer tube stop 848 optionally serves as aseal to block such leakage into the blood stream.

Optionally, the stops between tubes 802 and 804 serve to keep workingfluid out of the blood and/or blood out of the working fluid.Optionally, the seal nearest the base of the catheter seals in workingfluid (e.g., and using the design of seal 514, faces inwards) and theseal nearest the tip of the catheter seals out blood (e.g., and in thedesign of seal 514, faces outwards).

In an exemplary embodiment of the invention, balloon 818 is inflated byusing a balloon in which a minimum inflation pressure is higher thanthat used for extension. In one example, a pressure of less than 4 or 2bar is used for extension and a pressure of at least 10 or 15 bar isused for inflation of balloon 818. In other embodiments, for example ifthere are many curves, the pressures may increase, for example, up to 10or 15 atmospheres for the advancing and 15-20 or more for the balloon.In other embodiments, the advancing is easier, and, for example,pressures of under 2 atmospheres serve for advancing, while pressures of4 atmospheres and above serve for balloon inflation. Optionally, apressure relief valve 850 is provided in base 840, so that high,inflation-suitable, pressures are not achieved in the working fluid.Once balloon 818 is to be inflated, the valve may be adjusted,deactivated or removed, for example. Alternatively or additionally, anoptional pressure valve 852 is provided between lumen 806 and balloon818 and is opened only by high pressures. Alternative, as describedbelow, a manually actuated valve is used.

Optionally, for example as described below, a push or vibrating wire isinserted through lumen 806, for example to help balloon 818 advance pastobstructions. This is optionally done via the opening of valve 850.

In an exemplary embodiment of the invention, when balloon 818 is to beinflated, tubes 802 and 804 are locked relative to each other. In oneembodiment, tube 804 is simply advanced to its end, and then (or at thesame time) the whole catheter retracted if needed so balloon 818 is in acorrect location relative to narrowing 106. Optionally, a pull wire suchas described in FIG. 4C is used for such locking.

In the embodiment shown, guide wire 108 exits balloon 818 through aguide wire port 22 in the base of balloon 818, and guide wire 108travels outside of catheter 800. In the embodiment shown, an externalholder 854 is provided, with a path 856 for arranging guide wire 108.

Coiled Storage

FIG. 8B shows a variant of FIG. 8A, in which a separate ballooninflation tube 860 is provided. This tube is optionally coiled up in astorage section 862. A cone-shaped guide opening 868 is optionallyprovided to help a coiled section 864 of tube 860 straighten out aspulled by tube 804. A proximal side of tube 860 is optionally attachedto a balloon inflation port 866.

Optionally, tube 860 is kept evacuated, so as to minimally interferewith catheter extension and/or to prevent pressure on tube 860 frominflating balloon 818. Alternatively, some amount of fluid is providedin tube 860, for example to assist it in leaving storage section 862 orto prevent kinking or piling up thereof. It should be noted that in someembodiments of the invention, for example in FIG. 4, it may be desirableto provide some fluid into the inner tube (402) to ensure the sealbetween the inner and outer tubes, which might be compromised by theinner tube collapsing.

External Storage

FIG. 8C shows a variant in which tube 860 is stored outside thecatheter, for example exiting base 840 via an opening 870 with anexternal fluid port 872. In such a case, tube 860 optionally serves as astopping mechanism such as described in FIG. 4C. In this and in otherembodiments, a tube section is optionally used to assist sealing. Forexample, a tube 861 may enclose tube 860 inside base 840 and help sealport 870 from the working fluid and/or to prevent tube 860 from beingcrushed by port 870. The fit between tubes 861 and 860 is optionallyrelatively close, to provide a sealing function. Optionally, a suitablesealant or coating is provided to enhance the seal.

Optionally, a tube such as tube 861 is used to seal between a catheterhub and an outer tube, in this or other embodiments.

Collapsed Lumen

FIG. 9A shows a catheter system 900, in which an inner tube 904 thereofis collapsed outside the human body, in accordance with an exemplaryembodiment of the invention. A single lumen 906 of tube 904 can be used,for example as described in FIG. 8A. Collapsing outside the human bodyallows a larger diameter storage section to be used than might bepossible or desirable inside the body. It is noted, however, that insome embodiments of the invention a large diameter vessel may be treatedas being outside the body for the purpose of providing a storage areafor a small-diameter catheter.

In the embodiment shown, a section 950 of tube 904 is axially collapsed,to have a form similar to that of a folded accordion. Section 950 isoptionally stored outside the body, for example, in a storage tube 952.Optionally, an outer tube 902 is provided, for example having a lengthof 1 meter, within which lies a corresponding section 954 of inner tube904, in uncollapsed condition. A feeding nozzle 956 optionally feedscollapsed section 950 into tube 902 or into a sheath (not shown).

FIG. 9C shows an exemplary design of section 950, in which when theaccordion shape is axially extended, pleats (such as found in balloons)optionally form along pre-defined bending lines. These pleats are foldedaround section 950 as it is pulled through nozzle 956. Optionally, ringsof a material with tensile strength are provided in section 850 (and/orin other accordion tubes described below), to prevent its expanding atundesired points. Section 950 is optionally created by inflation of tube904 into a form with multiple axially separated expansion areas.

Referring back to FIG. 9A, an inner tube or wire 958 is optionallyprovided to help nozzle 956 form and/or fold such pleats. Optionally,one or more holes 960 in tube 958 provide fluid which pushes the pleatsoutwards.

In use, fluid pressure is increased via a fluid port 942 of a basesection 940 of catheter 900. The increased fluid volume pushes at aballoon section 918 of catheter 900, which pulls some of section 950 outof nozzle 956 and forward.

Optionally, a wire 943 is provided to selectively stop the advance ofballoon 918 and/or allow its inflation without advancing. Optionally, ifwire 943 is not attached along an axis of catheter 900, the combinedeffect of applying pressure and preventing advance of wire 943 willcause turning of the tip of balloon 943, which may be used fornavigation. A similar mechanism may be used in other embodiments of theinvention as well.

FIG. 9B shows a design of an exemplary self-sealing valve port 947, inwhich increased pressure (e.g., balloon inflation pressure) causes alocking of wire 943. In the design shown, a cone shaped section 945 ofport 947 is urged into port 947 (as formed in base 940). As pressureincreases it is more strongly urged. The cone shape causes increasedpressure on wire 943, and this increased friction, as the cone is pushedin more. Optionally, port 947 is made fast responding. Alternatively, itmay be slow responding. Once activated, port 947 is optionally releasedby being manually pushed in.

Double Collapsed Lumen

FIG. 10 shows a catheter system 1000 similar to that of FIG. 9A, exceptthat a separate tube 1060 is provided for inflation of a balloon section1018 of catheter 1000, in accordance with an exemplary embodiment of theinvention. In the embodiment shown, tube 1060 is also foldedaccordion-like. However, it may be stored in a different manner, forexample being coiled or folded or extending out of a base 1040 ofcatheter 1000. A feeding nozzle as in FIG. 9A is optionally provided.

In an exemplary embodiment of the invention, base 1040 includes twoports, one for inflating balloon 1018 and one for extending an innertube 1004 thereof. Alternatively, as shown, a single port 1042 is usedwhich can be selectively attached to tube 1060 or tube 1004. In theexemplary method shown, port 1042 is mounted on a rotating section 1062and includes an off-center axial lumen 1064. Base 1040 includes twooff-center lumens at different angular positions, a lumen 1066 attachedto tube 1002 and a lumen 1068 attached to tube 1060. Rotation of section1062 selectively aligns its lumen 1064 with one or the other of lumens1066 and 1068, thus selecting the effect of increased fluid pressure.

Axially Folded Lumen

FIG. 11 shows a catheter system 1100 in which a single lumen iscollapsed by axial folding thereof, in accordance with an exemplaryembodiment of the invention. A folded section 1150 of an inner tube 1104is stored in a storage tube (or other geometry) 1152 outside the body.When fluid pressure is provided through a fluid port 1142, a balloonsection 1118 of catheter 1100 is pushed forward, pulling behind it tube1104. This causes part of section 1150 to unfold and be fed distally. Asin FIG. 9A, an outer tube and/or a feeding nozzle are optionallyprovided. Optionally, at least section 1150 is tapered, to assistfolding.

Collapsed Balloon Tube

FIG. 12 shows a back section of a catheter system 1200, in which aseparate tube 1260 is provided for a balloon section 1218 (not shown) ofcatheter 1200, in accordance with an exemplary embodiment of theinvention.

This back section may be used with many of the catheter designsdescribed herein, in which a separate tube is provided for inflation ofballoon 1218, for example, for FIGS. 6-8, 10 and 11. In the case ofcatheter system 1000, for example, a balloon tube 1260 may be folded upin a storage section 1252 which is proximal of storage tube 1052. Afeeding nozzle 1256 is optionally provided for feeding tube 1260. Asimilar design (or other storage designs described herein) may be usedfor the inner tube in those or other embodiments. Also it is noted thata separate balloon inflation tube may be added in various embodiments,even where none is shown in the figure.

While tube 1260 is shown as having a diameter significantly smaller thanthat of a lumen 1206, it may be of similar diameter or even act as aninner tube (e.g., as tube 604 of catheter 600 in FIG. 6 or in FIG. 4).While tube 1260 is shown as folded in a pleat fold, it may be arrangedotherwise, for example, coiled or folded in a spiral manner (e.g., FIGS.8B and 8C). In use, fluid pressure is provided through a port 1242 andwhen this advances balloon section 1218, it pulls tube 1260 along withit and out of storage section 1252. Optionally, a separate fluid port1264 is provided for tube 1260.

Optionally, storage section 1252 is flexible so that pressure on it(e.g., adjacent nozzle 1256) can stop feeding of tube 1260 and possiblyhalt the extension of the catheter.

Alternatively or additionally, storage section 1252 is squeezable or isattached to a squeeze bottle, for increasing working fluid pressure.

Mechanical Force Application

FIG. 13 shows a catheter system 1300, with a single lumen 1306, in whicha mechanically actuated valve 1370 is provided, to selectively allowinflation of a balloon section 1318 thereof, in accordance with anexemplary embodiment of the invention. In general, catheter 1300 issimilar to catheter 800 (FIG. 8A), in that increase of fluid pressure inlumen 1306 of an inner tube 1304 causes inner tube 1304 to advancerelative to an outer tube 1302.

Unlike the embodiment shown in FIG. 8A, however, valve 1370 is providedto prevent inadvertent entry of fluid into balloon 1318. In theembodiment shown, a gasket section 1372 of valve 1370 selectivelyprevents flow of fluid into a port 1374 of balloon 1318. Optionally,port 1374 is an aperture in a base of balloon 1318, which also acts as alimiter 1380 for forward motion of gasket 1372. Once advancing of tube1304 is competed, a wire 1376 attached to gasket 1372 is pulled back,unsealing port 1374. Gasket 1372 is optionally attached to limiter 1380(not as shown), for example to limit retraction of gasket 1372.

When the valve is opened, increase of fluid pressure in lumen 1306 willcause balloon 1318 to expand. Inner tube 1304 is optionally fullyadvanced or locked to outer tube 1302, to prevent its further extension,for example, by attaching a brake on its outside section or providing aseparate stop wire, as in FIG. 4C. A back motion limiter 1378 isoptionally provided to prevent too far a retraction of gasket 1372.

Optionally, when gasket 1372 reaches back limiter 1378, further fluidflow in lumen 1306 is blocked and/or may be used to retract balloon1318. Alternatively, gasket 1372 may be floppy or the stop apertured, sothat such flow is not stopped. Optionally, this is useful whenretracting tube 1304 and/or catheter 1300, to prevent fluid from lumen1306 from entering balloon 1318 and re-inflating it.

Optionally, wire 1376 can be retracted against limiter 1380 to pull backballoon 1318 and/or tube 1304, for example past an obstruction, or asmall distance. Optionally, wire 1376 is provided through a wire port1382 in a base section 1340 of catheter 1300. For example the portdesign of FIG. 4C may be used, in which increase fluid pressure enhancesthe seal.

It should be noted that this design of valve 1370 operates automaticallyin that unless wire 1376 is purposely manipulated, valve 1370 will closeupon fluid pressure increase, blocking further inflation of the balloon.

When an obstruction is reached in advancing tube 1304 (e.g., a narrowingin the blood vessel or narrowing 106), sudden impulses of pressure maybe provided. Automatic closing of valve 1370 optionally preventsinadvertent inflation of balloon 1318.

Alternatively or additionally, wire 1376 is used to apply force toballoon 1318, helping advance it past obstructions, or for advancingballoon 1318 a small (e.g., 10 mm) or large amount (e.g. 100 mm).Alternatively or additionally, wire 1376 is used to vibrate balloon1318, for example, to help go past obstructions. Thus, wire 1376 may beused for application of mechanical force to a forward section ofcatheter 1300. Optionally, balloon 1318 is slightly inflated to helpwiden a narrowing it is pushed past.

In some embodiments of the invention wire 1376 is used for extendingtube 1304, or if only a single tube is provided, catheter 1300, insteadof a fluid column in lumen 1306.

Optionally, wire 1376 is curved and is used for navigation (e.g., toturn catheter 1318).

Alternative Back Limiter

FIGS. 14A and 14B show a catheter system 1400, similar to catheter 1300,with a different back limiter 1478 design in a valve 1470, in accordancewith an exemplary embodiment of the invention. FIG. 14A is moreschematic, while FIG. 14B is a generally to scale version of aparticular implementation of the catheter of FIG. 14A.

Unlike limiter 1378 of FIG. 13, limiter 1478 is an annular ring withslots formed along its inner circumference, such that a diameter at theslotted sections is greater than a diameter of a gasket 1472 and thediameter at the non-slotted portions is smaller than the diameter ofgasket 1472. Thus, even with gasket 1472 pulled back against limiter1478, fluid flow past back limiter 1478 is possible. Optionally, thediameter of a lumen 1406 of an inner tube 1404 at limiter 1478 isincreased to be greater than that of gasket 1472.

In an alternative embodiment, a back section 1488 of gasket 1472 isslotted and cone shaped and a plain ring may be used for limiter 1478.In this embodiment the maximal diameter of gasket 1472 is smaller thanan inner diameter of an inner tube 1402 at the area of limiter 1478. Ifport 1474 is smaller in diameter than lumen 1406, gasket 1472 optionallyhas a diameter substantially smaller than that of lumen 1406.

It should be noted that pulling back or holding a wire 1476 of valve1470 can be used to prevent advance of inner tube 1404 while a balloon1418 thereof is inflated.

It should be noted that a valve as described herein may be used forother purposes, for example allowing selective sampling of blood and/orblood pressure in the body, or injection of pharmaceuticals or contrastagents. Such fluids can enter or leave (in this or in other embodiments)via the lumen which would otherwise be used to pressure balloon 1418.

FIG. 14B is a cross-sectional view generally to scale of animplementation of catheter 1400. It shows an implementation, in whichback limiter 1478 is an elongate tube with axially elongate slots 1479.

Rotating Valve

FIGS. 15A and 15B show a catheter system 1500, similar to that of FIG.13, with a rotating valve 1570 design, in accordance with an exemplaryembodiment of the invention. Again, FIG. 15A shows an schematic diagramand FIG. 15B shows an implementation generally to scale.

In catheter 1500, a gasket 1572 is selectively rotated by a wire 1576,so that an aperture 1592 therein selectively matches a balloon port1574, both optionally of axis. Optionally, gasket 1572 sits in anarcuate slot 1594, which prevents retrograde motion thereof. Slot 1594is optionally missing adjacent balloon port 1574. Optionally, a rotationstop 1596, for example a peg that extends proximally axially past slot1594, is provided on gasket 1572, to allow identification of its openingstate and/or to simplify usage. For example, a maximal clockwiserotation will indicate (or cause) an open valve, and a maximalcounter-clockwise rotation will cause a closed valve. Alternatively oradditionally, a slot 1598 is formed on gasket 1572, and extends onlypart of an arc and rides on a peg or arcuate section 1599 which iscoupled to a non-moving part of valve 1570.

Inner and Outer Motion

In the embodiments described herein, both motion of the inner tube andmotion of the outer tube, are provided. Potential advantages of innertube motion include less friction against an enclosing tube/body lumen,smaller diameter and use of the inner tube for balloon inflation as wellas extension. Potential advantages of outer tube motion include,increased force at tip and better sealing against leakage. As can beappreciated, the designs shown herein may be varied to have inner orouter tube motion.

Similarly there are advantages and disadvantages to the variations ofhaving working fluid inside the inner tube or between the tubes. Oneconsideration is sealing. Another is distance of application of forcefrom the catheter tip. Another is effective hydraulic cross-section.

It should be noted that leakage of fluid past a seal (or if no seal isprovided) may have the advantage of acting as a pressure release valve,which prevents over-pressuring. In some implementations, high pressuresmay degrade the controllability, possibly causing freezing or jumping.Leakage reduces these pressures, if inadvertently achieved, andincreases controllability. In other embodiments, such a leak is used toprovide the working fluid, possibly including a pharmaceutical, to adesired area. In should be noted that leakage of saline fluid isgenerally not a physiological problem.

Outside Inflation Tube

FIG. 16 shows a catheter system 1600, in which a balloon inflation tube1605 is external to an inner tube 1604. In use, pressure is providedthrough a port 1642 to a base 1640, causing inner tube 1604 to advancerelative to an outer tube 1602. Once advancing is completed, inner tube1604 is removed and inflation tube 1605 is used for inflating of aballoon 1618.

Tools

The above description has focused on balloons as a tool which isprovided using the catheter. Other tools maybe provided in addition toor instead of a balloon. In one example, the lumen is used for providingother fluids, such as contrast material or a pharmaceutical.Alternatively or additionally, the balloon is a sweating balloon forproviding such pharmaceuticals. Alternatively or additionally, theballoon is used to provide radioactive treatment

Alternatively or additionally, other tools are provided, for example, ananeurysm treatment coil, a basket, RF ablation (e.g., using the lumenfor wires), a drill, forceps, a closure devices (e.g., for septaldefects). In an exemplary embodiment of the invention, a coil is pushedout of the lumen using an increased pressure in the lumen. In anotherexample, a pull wire in the lumen is used to deploy a basket. This, itcan be seen that in some embodiments of the invention the working fluidused to advance the balloon and/or tubes used for carrying this fluid,may perform double duty in activating a tool.

Testing

Optionally, one or more of the following tests are applied during orafter manufacture, to some or all of the catheters:

-   -   (a) determination if movement profile (e.g., in response to        force and/or volume) is uniform;    -   (b) detecting leaks; and    -   (c) measuring friction (static and/or dynamic), at one or more        locations along the catheter.

Optionally, some testing is done outside the body before use, forexample making sure that the catheter works (e.g., test extending),checking for leaks and/or familiarizing a physician with the catheters.

In filling the catheter with fluid, a priming step is optionallyperformed in which fluid is dripped into the catheter, while the hub isheld up and the balloon is down. Optionally vibration is used to reduceair bubbles. Optionally, the catheter is stored in vacuum.

While the above catheter system has been described in general for anytype of blood vessel, it should be appreciated that particularmodifications may be desired for certain vessel types. For example,different coronary vessels have different diameters and distances fromthe aorta, thus suggesting different catheter lengths, stiffnesses anddiameters.

Measurements are provided to serve only as exemplary measurements forparticular cases. The exact measurements stated in the text may varydepending on the application, the type of vessel (e.g., artery, vein,xenograft, synthetic graft), number of turns, distance of treatment areafrom a major blood vessel, type of tool, and/or diameter of vesselsinvolved (e.g., 1 mm, 2 mm, 3 mm, 5 mm, aorta sized).

While the term “tube” and other geometrical shapes have been describedand used for generality, it should be appreciated that this tube neednot have a full body nor have a circular cross-section, in someembodiments.

It will be appreciated that the above described methods of catheteradvancing and extending may be varied in many ways, including, changingthe order of steps and the types of tools used. In addition, amultiplicity of various features, both of method and of devices havebeen described. In some embodiments mainly methods are described,however, also apparatus adapted for performing the methods areconsidered to be within the scope of the invention. It should beappreciated that different features may be combined in different ways.In particular, not all the features shown above in a particularembodiment are necessary in every similar embodiment of the invention.For example, the following features can be used in various embodiments:seal types, stop types, offsets, location of working fluid, balloonlumen storage, pressure-based control, extension controllers and valves.Further, combinations of the above described features, also fordifferent embodiments, are also considered to be within the scope ofsome embodiments of the invention. Also within the scope of theinvention are surgical kits which include sets of medical devicessuitable for performing, for example, a single or a small number ofcatheter based procedures. In some embodiments, one or more of thedevices, generally sterilize, described above, are packaged and/or soldwith an instruction leaflet, describing the device dimensions and/orsituations for which the device should be applied. Section headingswhere are provided are intended for aiding navigation and should not beconstrued to limiting the description to the headings. When used in thefollowing claims, the terms “comprises”, “includes”, “have” and theirconjugates mean “including but not limited to”.

It will be appreciated by a person skilled in the art that the presentinvention is not limited by what has thus far been described. Rather,the scope of the present invention is limited only by the followingclaims.

1. A catheter for use in a blood vessel, comprising: an elongate bodyhaving an axis, a lumen along said axis, a proximal opening at one end,connected to the lumen and a front tip at a distal end of the body; anelongate body section, wherein said elongate body is configured foraxial motion of at least 50 mm relative to said second elongate bodysection; and an elongate hydraulic fluid column in said lumen andadapted to apply a pushing force to said front tip in a distaldirection, said force being applied at an application point, said forcebeing suitable for extending said tip at least 50 mm relative to saidelongate body.
 2. A catheter according to claim 1, wherein saidapplication point is nearer said front tip than said proximal opening.3. A catheter according to claim 1, wherein said proximal opening isadapted to be outside a human body, when the catheter is in use.
 4. Acatheter according to claim 1, wherein said catheter is configured sothat said liquid material does not drain into said blood vessel.
 5. Acatheter according to claim 1, wherein said column is adapted to beadvanced from outside a body.
 6. A catheter according to claim 1,wherein said body comprises a collapsed tube which extends from said tipto outside of said body and which said pushing force extends collapsedtube.
 7. A catheter according to claim 1, wherein said tip pulls along aportion of said catheter, having a length of at least 5 times a diameterof the catheter, said length being pulled by said tip when pushing forceis applied to said tip.
 8. A catheter according to claim 1, wherein saidbody comprises a first, inner, tube and a second, outer tube, said tubesat least partially axially overlapping, wherein said pushing forceextends one tube relative to the other tube.
 9. A catheter according toclaim 8, wherein said tip pulls at least a portion of said one tube withit when pushing force is applied to said tip.
 10. A catheter accordingto claim 9, wherein said pulled section is too soft to be reliablypushed a distance of more than 500 mm in a human body, when the catheteris in use.
 11. A catheter according to claim 9, wherein said tip pullsalong a tube other than said tubes when pushing force is applied to saidtip.
 12. A catheter according to claim 9, wherein at least a portion ofsaid one tube is adapted to be stored outside a human body when thecatheter is in use and extends out of a catheter base of said catheter.13. A catheter according to claim 9, wherein at least a portion of saidone tube is adapted to be stored outside a human body, when the catheteris in use, in a configuration having a shortened axial dimension.
 14. Acatheter according to claim 8, wherein said inner tube extends when saidforce is applied.
 15. A catheter according to claim 8, wherein saidouter tube extends when said force is applied.
 16. A catheter accordingto claim 8, wherein only one of said inner and said outer tubessubstantially extends when said force is applied.
 17. A catheteraccording to claim 8, wherein said fluid column is carried between saidtwo tubes.
 18. A catheter according to claim 8, wherein said fluidcolumn is carried within the inner tube.
 19. A catheter according toclaim 8, comprising a tool attached at said tip.
 20. A catheteraccording to claim 19, wherein said tool comprises a balloon attached atsaid tip.
 21. A catheter according to claim 20, comprising a separatetube with a lumen for inflating said balloon.
 22. A catheter accordingto claim 20, wherein said balloon is attached to a metallic inflationtube.
 23. A catheter according to claim 20, wherein said inner tubeserves as a lumen for inflating said balloon.
 24. A catheter accordingto claim 23, wherein said inner tube serves as a lumen for inflatingsaid balloon and not for said fluid column.
 25. A catheter according toclaim 20, wherein said balloon is inflated via a lumen which carriessaid fluid column.
 26. A catheter according to claim 25, wherein saidballoon is inflated using a higher pressure than used for extending saidcatheter.
 27. A catheter according to claim 25, comprising a valve atsaid balloon for selectively allowing liquid flow into said balloon. 28.A catheter according to claim 27, wherein said valve is a pressuresensitive valve.
 29. A catheter according to claim 27, wherein saidvalve is an externally actuated valve.
 30. A catheter according to claim29, wherein said valve is a stop valve in which a block is retractedfrom a port to said balloon to allow fluid under pressure to enter theballoon.
 31. A catheter according to claim 29, wherein said valve is arotating stop valve having at least two configurations, and in which ablock is rotated from one configuration to a second one of saidconfigurations to selectively seal or not seal a port to said balloon.32. A catheter according to claim 21, wherein said balloon inflationtube is adapted to be stored outside a human body, when the catheter isin use.
 33. A catheter according to claim 32, wherein said tube isstored in an axially collapsed state.
 34. A catheter according to claim8, wherein said tube is adapted to extend at least 50 mm.
 35. A catheteraccording to claim 8, wherein said one tube is adapted to extend atleast 150 mm.
 36. A catheter according to claim 8, wherein said one tubeis adapted to extend at least 250 mm.
 37. A catheter according to claim8, wherein said one tube is adapted to extend no more than 500 mm.
 38. Acatheter according to claim 8, comprising at least one stop whichprevents relative motion between the two tubes greater than a pre-setdistance.
 39. A catheter according to claim 38, wherein at least one ofsaid at least one stop is outside of said body.
 40. A catheter accordingto claim 38, wherein at least one of said at least one stop is not incontact with said fluid.
 41. A catheter according to claim 38, whereinsaid at least one stop comprises a wire extending out of said catheterand at least one movable brake section mounted on said wire.
 42. Acatheter according to claim 38, wherein said stop, when engaged,prevents liquid flow therethrough.
 43. A catheter according to claim 38,wherein said stop, when engaged, does not prevent liquid flowtherethrough.
 44. A catheter according to claim 38, wherein said stop,is located within 50 mm of a proximal end of the extending tube.
 45. Acatheter according to claim 38, wherein said stop, is located at adistance of at least 50 mm from a proximal end of the extending tube.46. A catheter according to claim 38, wherein when said tube is fullyextended, said stop is located at a distal end of the non-extendingtube.
 47. A catheter according to claim 38, wherein when said tube isfully extended, said stop is located at a position spaced less than 50mm from a distal end of the non-extending tube.
 48. A catheter accordingto claim 38, comprising a plurality of axially spaced stops.
 49. Acatheter according to claim 38, wherein said stop is an element axiallyshorter than 5 mm.
 50. A catheter according to claim 38, wherein saidstop is an element axially longer than 5 mm.
 51. A catheter according toclaim 8, comprising at least one seal between said tubes.
 52. A catheteraccording to claim 51, wherein said at least one seal is adapted for aparticular outer tube inner diameter.
 53. A catheter according to claim51, wherein said at least one seal is adapted for a range of outer tubeinner diameters.
 54. A catheter according to claim 51, wherein said atleast one seal comprises a plurality of axial spaced seals.
 55. Acatheter according to claim 51, wherein said at least one seal comprisesonly a single seal.
 56. A catheter according to claim 51, wherein saidat least one seal acts as a stop for preventing over-extension of saidone tube.
 57. A catheter according to claim 8, comprising an extensionlimiter which prevents steps of extension greater than a pre-setdistance.
 58. A catheter according to claim 57, wherein said pre-setextension step limitation is user-settable.
 59. A catheter according toclaim 8, comprising a lock configured to selectively lock said innertube to said outer tube and preventing motion.
 60. A catheter accordingto claim 8, comprising a lock configured to selectively couple saidouter tube to said body.
 61. A catheter according to claim 8, comprisinga pressure valve configured to release pressure of said working fluidabove a certain liquid pressure.
 62. A catheter according to claim 8,comprising a controller configured to control extension of said onetube.
 63. A catheter according to claim 62, wherein said controller isadapted to extend said tube by a controlled amount.
 64. A catheteraccording to claim 62, wherein said controller is adapted to extend saidtube by setting a pressure level to be achieved in said liquid.
 65. Acatheter according to claim 62, wherein said controller is adapted toadvance said catheter.
 66. A catheter according to claim 62, whereinsaid controller is adapted to synchronize a locking of said catheterwith inflation of a balloon portion of said catheter.
 67. A catheteraccording to claim 62, wherein said controller is adapted to retractsaid tube relative to said catheter.
 68. A catheter according to claim67, wherein said controller is adapted to synchronize said retractionwith advancing of said catheter.
 69. A catheter according to claim 8,comprising a guiding sheath surrounding said tubes.
 70. A catheteraccording to claim 8, comprising a guide wire, wherein said catheter isadapted to ride on said guide wire.
 71. A catheter according to claim70, wherein said catheter is configured so that said guide wire passesthrough said inner tube to outside a human body, when the catheter is inuse.
 72. A catheter according to claim 70, wherein said catheter isconfigured so that said guide wire passes between said inner tube andsaid outside tube to outside a human body, when the catheter is in use.73. A catheter according to claim 70, wherein said catheter isconfigured so that said guide wire passes outside of said outside tubeto outside a human body, when the catheter is in use.
 74. A catheteraccording to claim 70, wherein said catheter is configured so that saidguide wire passes outside of a guiding sheath to outside a human body,when the catheter is in use.
 75. A catheter according to claim 70,comprising a balloon at said tip.
 76. A catheter according to claim 75,wherein said guide wire passes through an inflation lumen of saidballoon.
 77. A catheter according to claim 75, wherein said guide wirehas a proximal exit from said balloon adjacent said balloon.
 78. Acatheter according to claim 77, wherein said balloon has a thick basefrom which said guide wire exits.
 79. A catheter according to claim 77,wherein said exit is less than 20 mm from said balloon.
 80. A catheteraccording to Claim 77, wherein said guide wire passes within aninflation lumen of said balloon.
 81. A catheter according to claim 75,wherein said guide wire exits said catheter from said extending tube ata point distal from a most distal point of said non-extending tube. 82.A catheter according to claim 75, wherein said guide wire exits saidcatheter from said extending tube at a point proximal to a most distalpoint of said non-extending tube.
 83. A catheter according to claim 75,wherein said guide wire passes through a seal between the two tubes. 84.A catheter according to claim 75, wherein said guide wire passes througha liquid path of said column ir said catheter.
 85. A catheter accordingto claim 75, wherein said guide wire passes only outside of a liquidpath of said column in said catheter.
 86. A catheter according to claim8, wherein said inner tube comprises a standard balloon catheter, notmanufactured for fluid control and wherein said liquid is carriedbetween said outer tube and said standard balloon catheter.
 87. Acatheter according to claim 8, wherein said inner tube comprises astandard balloon catheter having an adjustable seal mounted thereon, andwherein said liquid is carried between said outer tube and said standardballoon catheter.
 88. A catheter according to claim 87, wherein saidouter tube is a guiding catheter.
 89. A catheter according to claim 8,wherein said outer tube has an outer diameter of less than 3 mm.
 90. Acatheter according to claim 8, wherein said outer tube has an outerdiameter of less than 2 mm.
 91. A catheter according to claim 8, whereinsaid outer tube has an outer diameter of less than 1 mm.
 92. A catheteraccording to claim 8, wherein said inner tube has an outer diameter ofless than 1.5 mm.
 93. A catheter according to claim 8, wherein saidinner tube has an outer diameter of less than 0.5 mm.
 94. A catheteraccording to claim 1, wherein said application point is less than 500 mmfrom a most distal point of said catheter.
 95. A catheter according toclaim 1, wherein said application point is less than 350 mm from a mostdistal point of said catheter.
 96. A catheter according to claim 1,wherein said application point is less than 70 mm from a most distalpoint of said catheter.
 97. A catheter according to claim 1, comprisingan offset element between said application point and said tip, whichapplication point conveys said force from said column towards said tip.98. A catheter according to claim 1, comprising a push wire adapted toapply a second force to said tip.
 99. A catheter according to claim 98,wherein said push wire applies said second force at a substantially sameaxial position as said application point.
 100. A catheter according toclaim 98, comprising a controller configured to allow a short advance ofsaid wire, suitable for passing a narrowing in a blood vessel.
 101. Acatheter according to claim 1, comprising a base hub adapted to remainoutside a human body, when the catheter is in use.
 102. A catheteraccording to claim 101, wherein said base hub has only a single port forliquid pressure.
 103. A catheter according to claim 101, wherein saidbase hub has a plurality of ports for liquid pressure.
 104. A catheteraccording to claim 103, wherein at least one of said ports has a coveradapted to remain closed when liquid inside said port is at 5atmospheres of pressure or more.
 105. A catheter according to claim 101,wherein said base hub comprises a pressure release valve.
 106. Acatheter according to claim 101, wherein said base hub comprises a portfor a guide wire.
 107. A catheter according to claim 101, wherein saidbase hub comprises a port for a pushing wire.
 108. A catheter accordingto claim 101, wherein said base hub comprises a port for a valve controlwire.
 109. A catheter according to claim 101, wherein said base hubcomprises a port for an extension restricting wire.
 110. A catheteraccording to claim 109, wherein said port is configured to lock saidwire when said base is pressurized above a pre-set pressure value. 111.A catheter according to claim 101, wherein said base hub comprises aselector configured for selecting which of a plurality of lumens of thecatheter fluid pressure will be coupled to.
 112. A catheter according toclaim 101, wherein said base hub comprises a closable opening suitablefor selectable user access to a lumen of the catheter through the door.113. A catheter according to claim 112, wherein said opening is adaptedto be quickly opened by hand.
 114. A catheter according to claim 101,wherein said base hub includes a catheter storage section having alength, wherein said length is less than 80% of a length of a cathetersection stored therein.